As I understand it the B747 canoe fairings were simply sized to cover the very complex mechanism for the flaps
Area Ruling is a means by which wave drag is reduced. Wave drag is a component of the aerodynamic drag on the aircraft wings and fuselage moving at transonic and supersonic speeds, due to the presence of shock waves. Wave drag is independent of viscous effects and tends to present itself as a sudden and dramatic increase in drag as the vehicle increases speed to the critical Mach number.
Aera ruling aims to make the sectional volume of the aircraft to smoothly increase from the nose and smoothly decrease at the tail. Some exmples.
F-102
F-106 - the F-102 redesigned with area ruling producing a 25% increase in speed
Concorde - having the "bump" reduced to fall inside the ideal line would have meant reducing the cabin diameter over those points, you can't satisfy all design criteria.
At the time of the 747 design area rule was well known and we have no idea of what was in the aerodynamic department minds. Positioning the under wing engine pods forward of the leading edge is another nod in the direction of area rule, But that positioning of engine pods was a feature on the B-47 and B-52 prior to Whitcomb coming out with his theory. The question is why Boeing adopted that particular feature, besides engineering issues such as wing bending relief etc. Did the post war Operation "Paperclip" give them some insight to what became Area Rule from the German research, or was the podded engine placement Area Rule effect just a serendipitous outcome resulting from other engineering concerns.
Whitcomb published his area rule paper in 1953 and it was classified "Restricted", in 1958 it was made public. His paper here,
https://ntrs.nasa.gov/api/citations/...0050019402.pdf